Phonon-assisted stimulated emission from pendeoepitaxy GaN stripes grown on 6H-SiC substrates

Abstract

Phonon-assisted stimulated emission has been demonstrated by photopumping GaN stripes grown via pendeoepitaxy on 6H-SiC (0001) substrates. Transverse-electric-polarized emission with well-defined Fabry-Ṕrot modes located at one longitudinal optical phonon energy (90 meV) below the band gap of GaN was observed at 77 K. An effective refractive index of 8.578 was obtained using a cavity length of 13.3 μm and a mode spacing of 0.6 nm. This value is significantly higher than the value previously reported in the literature using ellipsometry, which indicates that the absorption loss is more severe during lasing when the excess carrier concentration is very high. © 2007 American Institute of Physics.